As this type of movable sensor device have been known an angular velocity sensor having as a movable sensor structure an angular velocity detecting structure that has a vibrator and detects an angular velocity, an acceleration sensor having as a movable sensor structure an acceleration detecting structure that has a movable electrode and detects an acceleration, etc.
Such a movable sensor device as described above is fixed to an object to be measured such as a vehicle or the like under the state that it is mounted in a package such as ceramics, metal or the like as a fixing member, for example, and practically used to detect yaw rate, acceleration, etc.
Under the practical use of the movable sensor device as described above, the mobility characteristic and the vibration characteristic of the movable sensor structure are affected by unnecessary vibration from the external or unnecessary vibration of the sensor device itself. Therefore, a vibration isolation structure has been adopted to prevent the movable sensor device from being affected by the unnecessary vibration as described above.
As the vibration isolation structure as described above, vibration isolating rubber for absorbing unnecessary vibration is interposed between the package and the movable sensor device (for example, JP-A-2000-55667; Patent Document 1), or the movable sensor device and the package are fixed to each other by adhesive agent having a vibration isolating agent (for example, JP-A-2003-21647; Patent Document 2).
As this type of movable sensor device has been proposed an MEMS (Micro Electro Mechanical Systems) type movable sensor device that actively uses the silicon semiconductor processing technique (JP-T-2003-530233; Patent Document 3).
This type of movable sensor device has a substrate, a micromechanical acting layer provided on the substrate, a coating layer provided on the micromechanical acting layer and an electrically conductive zone layer provided on the coating layer.
The coating layer has a monocrystalline area and a polycrystalline area, and the monocrystalline area and the polycrystalline area are epitaxially grown on a monocrystalline area and a polycrystalline starting layer that exist under the monocrystalline area and the polycrystalline area, respectively.
Furthermore, the micromechanical acting layer has a monocrystalline area and a polycrystalline area, the monocrystalline area and the polycrystalline area are epitaxially grown on a monocrystalline area and a polycrystalline starting layer that exist under the monocrystalline area and the polycrystalline area, and a movable sensor structure is formed in the polycrystalline area of the micromechanical acting layer.
However, the above-described techniques separately require a vibration isolating function member such as the vibration isolating rubber or the adhesive agent having the vibration isolating function as described above when the movable sensor device is mounted to a fixing member. Therefore, various problems occur such as a cost-up problem caused by increase of the number of parts, degradation of the vibration isolating function due to time-variation of the joint portions of the movable sensor device, the vibration isolating function member and the fixing member or the vibration isolating function member itself, that is, the degradation of the sensor characteristic.